Conventionally known frames that are used in buildings include, for instance, the building frame for steel-structure housing disclosed in Patent Document 1.
The building frame disclosed in Patent Document 1 comprises a first H-section steel, a second H-section steel that is joined to an opening of a groove of the first H-section steel, in a state where a leading end section of the second H-section steel is butting against the first H-section steel, and a section-steel jointing fitting for joining the second H-section steel to the first H-section steel.
The first H-section steel has a web and a pair of flanges that flank the web from above and below. The section-steel jointing fitting fits between both flanges in such a way so as to come into close contact with both flanges of the first H-section steel. Through fitting of the section-steel jointing fitting between both flanges (within the groove) of the first H-section steel, the section-steel jointing fitting contributes also to reinforcing the first H-section steel.
The second H-section steel is joined to the section-steel jointing fitting that is fitted between both flanges of the first H-section steel.
In some instances, C-section steels are used, instead of H-section steels, as frames that are utilized in buildings. Specifically, one such C-section steel has herein a web, a pair of flanges that rise from both ends of the web, and respective lips that bend inward from the flanges.
The size of the section-steel jointing fitting disclosed in Patent Document 1 is such that the section-steel jointing fitting comes into contact with both flanges. However, the spacing between the lips of the C-section steel is narrower than the spacing between the flanges. Accordingly, the lips constitute an obstacle upon attempting to attach the section-steel jointing fitting by passing the section-steel jointing between the lips of the C-section steel.
The section-steel jointing fitting disclosed in Patent Document 1 can conceivably be made smaller than the spacing between both lips of the C-section steel. Doing so, however, gives rise to a gap between both flanges of the C-section steel and the section-steel jointing fitting, whereby the flanges can no longer be supported from the inside by the section-steel jointing fitting. The reinforcement effect of the C-section steel that is elicited by the section-steel jointing fitting becomes weaker as a result.
Patent Document 1: Japanese Unexamined Patent Application No. 2002-327495